ABSTRACT
Mice lacking expression of the ß2 subunit of the neuronal nicotinic acetylcholine receptor (CHRNB2) display abnormal retinal waves and a dispersed projection of retinal ganglion cell (RGC) axons to their dorsal lateral geniculate nuclei (dLGNs). Transcriptomes of LGN tissue from two independently generated Chrnb2-/- mutants and from wildtype mice were obtained at postnatal day 4 (P4), during the normal period of segregation of eye-specific afferents to the LGN. Microarray analysis reveals reduced expression of genes located on the cell membrane or in extracellular space, and of genes active in cell adhesion and calcium signaling. In particular, mRNA for cadherin 1 (Cdh1), a known axon growth regulator, is reduced to nearly undetectable levels in the LGN of P4 mutant mice and Lypd2 mRNA is similarly suppressed. Similar analysis of retinal tissue shows increased expression of crumbs 1 (Crb1) and chemokine (C-C motif) ligand 21 (Ccl21) mRNAs in Chrnb2-/- mutant animals. Mutations in these genes are associated with retinal neuronal degeneration. The retinas of Chrnb2-/- mutants are normal in appearance, but the increased expression of these genes may also be involved in the abnormal projection patterns of RGC to the LGN. These data may provide the tools to distinguish the interplay between neural activity and molecular expression. Finally, comparison of the transcriptomes of the two different Chrnb2-/- mutant strains reveals the effects of genetic background upon gene expression.
Subject(s)
Cell Adhesion/physiology , Nerve Degeneration/metabolism , Receptors, Nicotinic/metabolism , Animals , Cadherins/genetics , Cell Adhesion/genetics , Immunohistochemistry , Mice , Mice, Mutant Strains , Nerve Degeneration/genetics , Oligonucleotide Array Sequence Analysis , Receptors, Nicotinic/genetics , Retinal Degeneration/genetics , Retinal Degeneration/metabolism , Retinal Ganglion Cells/metabolism , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Brain opioid systems have been implicated in the regulation of social interaction, including agonistic behaviour. kappa-Opioid receptor B and C mRNA levels were decreased in the ventral tegmental area but not in the nucleus accumbens in male mice with repeated experience of social victories (winners), but not in mice after social defeats (losers) after 10 but not 20 days of confrontations. mu-Opioid receptor mRNA levels were not changed.
